When using wear plates of the kind referred to as walls or linings for such walls in a mold-making press in positions, in which the finished mold or mold part is removed from the press by being moved along the mold chamber in sliding engagement with the wear plate, it is imperative that the nozzle members are perfectly flush with the surface of the wear plate facing the mold chamber. Otherwise,
if the nozzle members protrude from said surface, they will score the mold part and be subjected to uncontrollable excessive wear on their edges, or PA0 if the nozzle members recede relative to said mold-chamber surface, then the "plug" formed on the mold or mold part will be sheared off during such movement, such action also causing uncontrollable excessive wear, in this case on the edges of the bores in the wear plate,
in both cases producing loose sand highly likely to disturb the various mold-making and/or subsequent casting operations, as well as causing a considerable reduction of the useful life of the wear plate.
Some prior-art nozzle members are adapted to be screwed into the wear plate from the latter's mold-chamber surface. These nozzle members are, however, difficult to align properly with the mold-chamber surface, as the tool used for screwing them in in many cases obscures the view. It is a further disadvantage with these nozzle members that, due to tolerance variations between the interengaging members, the engagement between the external screw-thread on each nozzle member and the internal screw-thread in the corresponding bore in the wear plate is not sufficiently stable to prevent the nozzle members from coming out of alignment.
Other prior-art nozzle members have been fitted into the respective bores by using a tight press fit, but experience has shown this arrangement to cause warping of the wear plate with the consequent need of re-grinding after the nozzle members have been fitted. Apart from being comparatively costly, such re-grinding will also remove at least a part of the specially treated or hardened surface layer on the wear plate thus also causing the useful life of the wear plate to be reduced.